The following disclosure relates to non-volatile memory (NVM), and in particular to magnetic random access memory (MRAM). MRAM offers comparable performance to volatile static random access memory (SRAM) and comparable density with lower power consumption to volatile dynamic random access memory (DRAM). Compared to NVM Flash memory, MRAM offers much faster access times and suffers minimal degradation over time, whereas Flash memory can only be rewritten a limited number of times.
An MRAM cell is formed by a magnetic tunneling junction (MTJ) comprising two ferromagnetic layers which are separated by a thin insulating barrier, and operates by tunneling of electrons between the two ferromagnetic layers through the insulating barrier. Scaling of MRAM memory cells in advanced technology nodes (i.e., Node 28 and beyond) is limited by the resolution limit of optical lithography. At the lower resolution limit of optical lithography MJT size variation between MRAM cells within an MRAM array can degrade memory performance.